Air chilling systems are often used with gas turbines to condition the inlet air temperature. Depending upon the ambient temperature, the use of the chilling systems with gas turbine engines may increase overall power output by a significant percentage. Specifically, the power output of the gas turbine is almost in reverse proportion to the inlet air temperature over a wide temperature range. For example, a known gas turbine may produce only about 154 megawatts of power at an ambient temperature of about 83 degrees Fahrenheit (about 28.3 degrees Celsius) but may produce about 171.2 megawatts of power at about 50 degrees Fahrenheit (about 10 degrees Celsius), an increase of more than about eleven percent. Likewise, the chilling systems may be run to temper the cold inlet air with waste heat in cooler ambient temperatures so as to provide efficient part load operation for the gas turbine.
One method of chilling the inlet air, as well as removing contaminants within the air stream, is through the use of a chilled water air washer system. Cooling the inlet air below about 40 degrees Fahrenheit (about 4.4 degrees Celsius) with a chilled water air washer system may be difficult in that it requires a reduction in the relative humidity and the dew point of the air stream. The temperature of the inlet air must be kept above the dew point so as to avoid condensation or freezing of the water contained in the air. Conventional chilling methods, however, may result in the air being very close to saturation, i.e., the relative humidity may be close to 100%. At this condition, the dew point is very close to the air temperature. As such, any further temperature loss may cause icing of components within or about the compressor inlet. These factors generally thus limit conventional inlet air cooling to about 38 to about 44 degrees Fahrenheit (about 3.3 to about 6.6 degrees Celsius).
There is thus a desire for improved gas turbine inlet air chilling systems. Such an inlet air chilling system should provide improved chilling of gas turbine inlet air while increasing overall system output and efficiency without the concern of freezing condensate.